Biomechanical Analysis of the Behaviour at the Metaphyseal-Diaphyseal Junction of Complex Tibial Plateau Fractures Using Two Circular Fixator Configurations

High-energy tibial plateau fractures are challenges in treatment with controversy over operative stabilisation, especially for fractures with metaphyseal-diaphyseal dissociation. Treatment with percutaneous or minimally invasive direct reduction techniques, usually associated with circular external fixation, has generated interest although there is no consensus regarding the type of external fixation to be used. This study aims to compare the two hybrid circular external fixation mountings used to treat the high-energy tibial plateau fractures. Two different groups of hybrid circular external fixation frame mountings were assembled using composite tibiae with proximal metaphyseal osteotomies simulating tibial plateau fractures with metaphyseal-diaphyseal dissociation. The standard all-wire frame mounting was assembled, and the comparison frame mounting had the distal K-wires replaced with half-pins. Both groups were tested through cyclic loading between 300 and 1000 N for 10,000 cycles. Interfragmentary linear and rotational displacements were analysed. The standard frame mounting behaved similarly to a classic Ilizarov frame, allowing greater axial movement (mean, 3.76 ± 0.26 mm in the standard group and 3.02 ± 0.23 mm in the test group) and smaller mediolateral displacement compared with the test frame (mean, 0.17 ± 0.16 mm compared to 0.56 ± 0.12 mm). The test frame behaved more similarly to a linear external fixator and provided greater axial stability, similar anteroposterior displacement, and lower mediolateral stability. Despite these differences, in both groups the axial displacement was greater than the prejudicial nonaxial movements. Increasing the number of half-pins and decreasing the number of K-wires in hybrid circular external fixation generate frames that tend to behave more similarly to the linear external fixators. Cardoso GS, Amorim R, Penha FM, . Biomechanical Analysis of the Behaviour at the Metaphyseal-Diaphyseal Junction of Complex Tibial Plateau Fractures Using Two Circular Fixator Configurations. Strategies Trauma Limb Reconstr 2020;15(3):138-145.